Pharmacokinetic delivery and metabolizing rate of nicardipine incorporated in

Pharmacokinetic delivery and metabolizing rate of nicardipine incorporated in
hydrophilic and hydrophobic cyclodextrins using two-compartment model
Sergey Shityakov and Carola Förster
E-mail: [email protected]
Department of Anaesthesiology, University of Würzburg, 97080 Würzburg, Germany
Abstract
Results
Results
The dispersion routes of cyclodextrin
complexes with nicardipine (NC), such as
hydrophilic hydroxypropyl-β-cyclodextrin
(NC/HPβCD) and hydrophobic triacetyl-βcyclodextrin (NC/TAβCD), through the
body for controlled drug delivery and
sustained release have been examined. The
two-compartment pharmacokinetic model
described the mechanisms how human body
handles with ingestion of NC-cyclodextrin
complexes in gastrointestinal tract (GI),
distribution in the blood (Plasma), and their
metabolism in the liver. The model showed
that drug bioavailability was significantly
improved after oral administration of
cyclodextrin complexes. The mathematical
significance of this study to predict
nicardipine delivery using pharmacokinetic
two-compartment mathematical model and
linear ordinary differential equations
approach represents a valuable tool to
emphasize its effectiveness and diminish the
side effects.
A
B
B
C
Fig. 2: Short-range GI (A) and plasma (B)
concentration profiles (ng/ml) for NC,
NC/HPβCD, and NC/TAβCD and their
metabolizing rates (C) as functions of time.
Methods
The
experimental
pharmacokinetic
parameters, such as maximum plasma
concentration (Cmax), the time to reach Cmax
(Tmax), and elimination half-life time (t1/2)
together with dissolution profiles were
taken from in vivo study of Fernandes and
coauthors. To simulate the NC dosedependent release and its metabolic
degradation we used computer liner algebra
algorithms in the Maple 15 software
(Maplesoft GmbH, Aachen, Germany). The
pharmacokinetic two-compartment model
included two different compartments: the
𝑑𝑥
first compartment (x(t) or ) describes the
𝑑𝑡
drug concentration in the GI and second
𝑑𝑦
(y(t) or ) describes its concentration in the
𝑑𝑡
plasma by following differential equations:
Conclusion
C
Fig.1: Loading of long-range GI and
plasma concentration-time profiles from a
dosage regime (D(t)) for NC (A),
NC/HPβCD (B), and NC/TAβCD (C)
chemical
compounds
after
oral
administration as functions of time.
𝑑𝑥
𝐷𝑊
=𝐷 𝑡
− 𝑥𝑡1/2
𝑑𝑡
𝐷𝑡
𝑑𝑦
= 𝑥𝑡1/2 − 𝑦𝑡1/2
𝑑𝑡
The NC release rate is the t1/2-dependent
process and, therefore, can be adjusted to
prolong and optimize ‘time release’
mechanism by controlling the formulation
ratio of its hydrophilic (NC/HPβCD) or
hydrophobic
(NC/TAβCD)
complexes.
Because y(t) is dose- and x(t)-dependent as
the level of the drug in the circulatory
system, it should last long enough for a drug
to be effective. With subsequent equal dose
levels for specified chemical compounds,
which are taken orally, the periodic plasma
concentrations were significantly prolonged
for the NC formulations, especially for
hydrophilic one, and maintained thereafter.
References
𝐷𝑊
𝑑𝑡
where D(t) is the drug dosage in mg/ml,
is the dissolution rate of NC in the GI, and
𝑡1/2 value is the half-life parameter either
for the GI or plasma.
Fernandes et al., 2003, J Control Release
(88)1: 127-134.
A